The 927 monoclonal antibody specifically recognizes CD317 which is also known as Bone marrow stromal antigen 2 (BST2) or Plasmacytoid Dendritic Cell Ag-1 (PDCA-1). CD317 (BST2) is a type II transmembrane glycoprotein that is encoded by Bst2. It is highly expressed on naïve plasmacytoid dendritic cells (pDC) which comprise very small populations within lymphoid and nonlymphoid tissues. pDC are characteristically early responders to viruses through Toll-like receptors (TLR), TLR7 and TLR9. Activated pDC can produce large amounts of proinflammatory cytokines including type I interferons, Interferon-alpha (IFN-α) and Interferon-beta (IFN-β), and are also known as Type I IFN producing cells (IPC). CD317 (BST2) expression can be upregulated on a variety of other cell types following stimulation with type I IFNs and IFN gamma including T cells, B cells, plasma cells, NK cells, CD8+ and CD8- dendritic cells, and cell lines. CD317 (BST2) may play a role in sorting proteins, eg, cytokines, from the Golgi apparatus and the plasma membrane.
The antibody was conjugated to BD Horizon™ BUV563 which is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This dye is a tandem fluorochrome of BD Horizon BUV395 which has an Ex Max of 348 nm and an acceptor dye. The tandem has an Em Max at 563 nm. BD Horizon BUV563 can be excited by the 355 nm ultraviolet laser. On instruments with a 561 nm Yellow-Green laser, the recommended bandpass filter is 585/15 nm with a 535 nm long pass to minimize laser light leakage. When BD Horizon BUV563 is used with an instrument that does not have a 561 nm laser, a 560/40 nm filter with a 535 nm long pass may be more optimal. Due to the excitation and emission characteristics of the acceptor dye, there may be spillover into the PE and PE-CF594 detectors. However, the spillover can be corrected through compensation as with any other dye combination.